package containers;//: containers/Groundhog2.java
// A class that's used as a key in a HashMap
// must override hashCode() and equals().

public class Groundhog2 extends Groundhog {
    public Groundhog2(int n) { super(n); }
    public int hashCode() { return number; }
    public boolean equals(Object o) {
      return o instanceof Groundhog2 &&
        (number == ((Groundhog2)o).number);
    }
} ///:~
